Quote:
Originally Posted by jr_ss
Personally, I'd ditch the P12 head, save yourself some money and frustration and buy a P11 head to work over. CFM differences are minimal at best between the two and the P12 has weaker valves than the P11. Not to mention limited availability for aftermarket parts on the P12. Think about what it costs for P12 head alone and then the amount of money you're going to drop into it in Port work. A worked over P11 head can and will flow the same as a worked over P12, just much easier to acquire and much cheaper to purchase.
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P12 being more expensive than a P11 is a misconception IMO. I bought a whole P12 engine and parted it out, wound up being cheaper since the P12 comes with a CAS and the single solenoid that doesn't need a relocation kit. The P12 cams resell for more than the P11s too (I went with N1s). Plus I didn't have to buy a front cover/oil pump or the oil pump spacer. Actually, when all is said and done, selling the extra parts and my old head, I might actually make some money. They've just been sitting in my basement though, I should get on that haha.
The part about the thinner valves is accurate though. I'm not too worried since the lighter valves means I can run lower spring pressures and the N1s also have a more delicate ramp up. As for parts availability, valve seals were like $10 off of a Nissan GA16 engine or whatever, springs are same as a DET and of course it can run the same cams as a P11.